Indicated for 12 V systems, this circuit was obtained in a 90s Siliconix documentation. The components used are from the time and current equivalents can be tested.
This circuit is from a 1995 technical documentation. The transistor can be a BC558 and the sensor...
Found in a Popular Electronics from the 90s, this circuit checks the presence of voltage on a...
The critical component of this amplifier is the output transformer. We found the circuit in an old...